Adenocarcinoma In Situ Arising from Brunner’s Gland Treated by Endoscopic Mucosal Resection

Figure 5

Immunohistochemical images. Proliferated Brunner’s glands are positive for MUC6 (a, white arrow) and negative for MUC5AC (b, white arrow). In contrast, most of the cells with gastric foveolar differentiation (a, black arrowhead; b, black arrowhead) and atypical cells (a, black arrow; b, black arrow) are positive for MUC5AC but are negative for MUC6. Both gastric foveolar metaplasia and atypical cells partly show dual positivity for MUC5AC and MUC6, particularly in the deeper layer (a, arrowhead; b, arrowhead). Some atypical cells showed relatively higher positivity for Ki-67 staining (c, hematoxylin and eosin staining, arrows).

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